Wal-Mart apologises as driver charged in accident that injured Tracy Morgan

Wal-Mart has apologised after a highway accident involving one of its truck drivers critically injured actor-comedian Tracy Morgan and prompted the US National Transportation Safety Board (NTSB) in a rare move to join a state investigation.

Kevin Roper, 35, of Jonesboro, Georgia, was charged in Middlesex County, New Jersey, with one count of death by auto and four counts of assault after the Wal-Mart tractor trailer he was driving crashed into a limousine van whose occupants included Morgan. A comedian travelling with the former Saturday Night Live television star was killed.

The six-vehicle accident, early on Saturday on the New Jersey Turnpike, occurred as US lawmakers consider ending rules designed to help prevent long-haul truck drivers from dozing at the wheel.

"This is a tragedy and we are profoundly sorry that one of our trucks was involved," Bill Simon, the president and chief executive officer of Wal-Mart US, said in a statement. "We are working quickly to understand what happened and are cooperating fully with law enforcement to aid their investigation."

Roper "failed to observe" slow-moving traffic ahead of him until it was too late, colliding with the limousine, said Gregory Williams, a sergeant first class with the New Jersey State Police. The limousine van, a 2012 Mercedes Sprinter, spun and then flipped over, Williams said. James McNair, 62, who was in the limousine van, was pronounced dead at the scene. Morgan, 45, who starred in the television comedy 30 Rock after leaving Saturday Night Live, was one of three people in the van who were critically injured.